The left-wing law professor ran on a promise to fight corruption, one of the conditions for entry into the European bloc, which Croatia is aiming to achieve by January 2012.

"We look forward to working with president-elect Josipovic on issues of common interest as Croatia heads into the final stage of accession to the European Union," State Department spokesman PJ Crowley told reporters.

"In that dialogue between Croatia and the EU obviously, effective governance is an important element, fighting corruption, cooperating with the International Tribunal for Yugoslavia."

Josipovic, 52, won the second round of Croatia's presidential election on Sunday with over 60 percent of the votes, and vowed to transform the nation into a "star" of Europe.